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20 Cards in this Set
- Front
- Back
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elements
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basic substances, 92 naturally occurring, compose all matter
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over 90% of the human body is composed of which 4 elements?
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hydrogen, carbon, oxygen, nitrogen
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atom
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the smallest unit of an element that still retains its chemical and physical properties
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protons
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located in the nucleus of an atom
carry a positive charge |
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neutrons
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located in the nucleus of an atom
carry no charge |
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electrons
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circle the nucleus in distinct orbits (like planets around the sun - except there are several of them in each orbit)
carry a negative charge |
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Which of the three subatomic particles (protons, electrons & neutrons) has almost no mass?
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electrons
atomic weight = # protons + # neutrons |
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isotope
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an atom of the same element but with a different # of neutrons (and therefore a different atomic weight)
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molecule
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atoms which have bound together to form a chemical unit
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compound
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atoms of different elements which have bound together
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ions
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positively or negatively charged particles
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acids
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substances that break up in water, releasing hydrogen ions (H⁺)
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bases
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substances that break up in water, either taking up hydrogen ions (H⁺) or releasing hydroxide ions (OH⁻)
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pH scale
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used to measure whether a substance is more acidic or alkaline, ranges from 0 (alkaline) -14 (acid)
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Water has a neutral pH. Why?
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When water molecules break up, they release equal amounts of H⁺ and OH⁻
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What is the pH of blood?
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about 7.4
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acidosis
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when the pH value of the blood drops below 7.35
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alkalosis
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when the pH value of the blood rises above 7.45
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buffers
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built in mechanisms of the body to prevent pH changes
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electrolytes
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substances that release ions in water
electrolyte balance is important because it affects vital organ function |
